Signaling Plan
This page outlines the plan for developing signals for the Colorado and Great Western Modular Railroad CGWRR. The CGWRR shall use the Modular Signal System MSS as the interface standard for signaling between modules. MSS utilizes a clever system of interconnects, plus current and optical detection to automatically propagate basic ABS signals as trains move throughout a layout. MSS mandates current detection on every layout module, and both curent detection and optical detection on every layout module containing a signal boundary not on every module boundary. By design, MSS will detect any rolling stock that draws current; for example, locomotives, lit passenger cars, lit cabooses,and FREDs will be detected. Clever use of current and optical detection can guarantee that the entire length of a train is signal-protected. However, it cannot protect cars that do not draw current - such as a hopper spotted on a siding, or a segment of a broken train stranded on the mainline - for that, each car will require one or more resistor-equipped wheelsets. MSS Requirements The Modular Signal System places several requirements on our railroad. Isolated Track Segments MSS requires each layout module's track segment(s) to be isolated from track segments on adjacent modules rail joiners on both rails. The module's track segment(s) must be powered by a dedicated module feeder wire from our "DCC track power" bus. This isolation is required to enable independent current detection on each module. Single versus Dual Mainline MSS is written for a single mainline. So our dual mainline will require two implementations - one for each mainline. Signaling the Yard We need to make decisions about the signaling requirements in the yard, and how much of yard information we want propagated to the mainlines. Resistor-Equipped Wheelsets Will we use resistor-equipped wheelsets? Resistors are only required if our signalling plan requires every car to be detected. MSS Integration with Non-MSS Modules MSS provides a well-defined standard interface into which we can connect Non-MSS modules. The best example of this is Hobo Junction. The wye at Hobo Junction and the complexity of its adjacent tracks - spread across five modules - makes it a poor candidate for using MSS; it should remain a Non-MSS module set. But the MSS Standard is sufficently well-defined to allow the boundaries of Hobo Junction to be MSS-compliant. Hobo Junction will not utilize MSS within its five modules, but at its three boundaries - the interconnects with ?name_of_adjacent_C_module?, ?name_of_adjacent_CC_module?, and the yard, MSS-compliant interfaces will be presented. [Effectively, the five modules of Hobo Junction will become one "Cascade Element" in MSS nomenclature. Our work with Team Digital logic boards will simply be enhanced to support MSS at the boundaries of Hobo Junction.] Hardware for the Modular Signal System Several manufacturers have prduced hardware for the Modular Signal System. The official list is at http://www.modularsignalsystem.info/MSSResources.html. MSS modules from Iowa Scaled Engineering are among the most favored designs. Iowa Scaled Engineering In the past, Iowa Scaled Engineering produced both an MSS Cascade Moduleand an MSS Crossover Module. Both of these products are now discontinued. However both products are "Open Source Hardware Association" projects, Creative Commons "Share Alike" projects, and , and "General Public License" projects, so their entire design file sets are available at GitHub. https://github.com/IowaScaledEngineering/mss-cascade https://github.com/IowaScaledEngineering/mss-crossover A resourceful model railroad club could reproduce any number of either of these MSS modules. And an even more resourceful club could use these as reference designs for custom implementations. CGWRR Implementation Initially, only eight ''MSS Cascade Elements ''plus active signals will be utilized - one element on each of the mainlines at the four primary outside corners of the layout. All other CGWRR Layout Modules will implement an ''MSS Crossover Element ''only - no active signals on each mainline. Once the four primary corners are signalled, the follow-on strategy is then to simply to "divide and conquer" by replacing selected Crossover Elements with Cascade Elements at our leisure - whenever and wherever we desire. Masthead Wiring In late 2018, the following signal masthead wiring was agreed upon Scott Coleman and Will Lohann. Where possible, all signals should be built with 2-lead 2-color LEDs, and wired to an 8p8t modular plug male. Wiring is designed to place the most important signal lenses LEDs in the center of the modular connector, with less important and optional lenses toward the outer edges of the connector. * Pin 1 - Mast2.HeadB.RedLED.Anode / GrnLED.Cathode ────────┐ * Pin 2 - Mast2.HeadA.RedLED.Anode / GrnLED.Cathode ──────┐ │ * Pin 3 - Mast1.HeadB.RedLED.Anode / GrnLED.Cathode ────┐ │ │ * Pin 4 - Mast1.HeadA.RedLED.Anode / GrnLED.Cathode ──┐ │ │ │ * Pin 5 - Mast1.HeadA.RedLED.Cathode/GrnLED.Anode ────┘ │ │ │ * Pin 6 - Mast1.HeadB.RedLED.Cathode/GrnLED.Anode ──────┘ │ │ * Pin 7 - Mast2.HeadA.RedLED.Cathode/GrnLED.Anode ────────┘ │ * Pin 8 - Mast2.HeadB.RedLED.Cathode/GrnLED.Anode ──────────┘